Method and apparatus for blowing bulbs



Patented July 29, 1 930 UNiTED STATES v1min-:lar ol-"Flcl-:A

CHARLES W. CRAIG,

COMPANY,

MErHoD ANnArrABATUs- Eon BLOWING BnLBs Application filed March 25, 1927. Serial No. 178,437.

My invention relates to methods and apparatus for blowing bulbs suitable forincandescent electric lamps and similar articles, and'more particularly to such methods and -5 apparatusinvolving the ysuction method of gathering molten glass as disclosed in Kadow Patent No. 1,021,048, issued March 26, 1912.

It has been the practice to gather a blank `from the molten glass, which vis usually contained in a tank, by a gathering-head comprising an .apertured vmold intowhich the molten glass is drawn by suction and to thereafter` cut oif the blank'by suitable knives attached to the mold. The shape ofthe blank has been as shownlin the Kadow patent above referred to, that is, with an intermediate flange extendingtherearound. The practice y has been to drop said blank from the gathering mold to the blowing spindle, the iiange and one end portion of the blank 'to the upper end of the' blowing spindle. As disclosed in the Kadow patent above referred to, the next stepis to drive a plunger contained inthe blowing spindle into the soft blank to form an initial' air chamber, the plunger afterwards being withdrawn. vSubsequently the spindle lis turned to bring the blank into lowermost position and the bulb is then blown.I y

rlhe `bulb produced by method has a moil pcrtionof'thick glass having an'opening therethrough of comparatively small diameter. Itis necessary ltoremove 7 this moil before the filament mount ofthe lamp or similardevice can` be insertedin the bulb and. Sealed' thereto. arate operation in 'lamp' making and adds to the cost of manufacture.` l l According to the method comprised by my invention, the shape of the blankis changed from that aboveA described to eliminatethe constricted end portion, and the blank is clamped and sealed lto' the blowing spindle simply by engagement withan' end flange as the endot which-carries a gripping device' which clamps' the above described glass 1s This requires a sep.

or EAST CLEVELAND, omo, nssieNoR To GENERAL ELECTRIC j `A CORPORATION or NEW Yom;

distinguished from an intermediate flange as no preliminary air chamber is necessary and mation is dispensed with. The bulb produced after the blowing operation has an end'neck ring ofl thickened glass, therethrough is not constricted but is of such diameter as to allow the passage of the filament mount for sealing in without necessitatingv a separate moil cutting off operation. While a bulb of this general construction is disclosed in Branin Patent 'No. 1,315,813 issued September 9, 1919, that bulb` was not actually produced by the suction gathering method vwith which my invention has to do, but by a press and blow method. One advantage of my invention is the saving in cost of manufacture.' Further features and advantages of my invention will appear from the description of a species thereof which follows.

In the drawing, Fig. 1 is a verticalsection of the suction mold and of a gathering head with the-registering end of a blowing spindle both made according to my invention; Fig. 2 is a vertical section of the end portion of the blowing spindlev with the parts in intermediate position; Fig. 3 is a similar View with the parts in final position; Fig. 4;V is a similar View showing the blown bulb; and Fig. 5 is a vertical section of the old style blank.

`the plunger which has been used for its fOr.-

but the openingv I The apparatus shown in Fig. A1 comprises ring 11 the blank mold 12 into which molten y drawn during thek gathering operation by suction applied through the pa .sage

13 in head 10 acting through apertures 14 in l the mold 12. lThe said mold has no laterally re-entrantJv portions such as formed by` neck mold sections of such moldsY as heretofore constructed and no intermediate ange is formed, therefore, pivoted knife 15 is provided for shearing ofl the blankafter the mold is filled. The blank on the blank. The usuall 16 is shownl as it is dropped upon the end of 90' the blowing spindle 17 which has the usual pivoted clamp portions 18 which are mounted for vertical downward movement after closing. In Fig. 2 the blank 16 is shown resting on the end of the blowinospindle 17 with the clamp portions 18 closedIiut elevated. In Fig. 3 the clamp portions 18 are shown in linal'clamping position compressing a circumferential external flange 19 at the end of the blank between the internal flange 20 of the clamp portions and the top .of the blowing spindle. The blank 16 is shown slightly altered in shape as-the blowing operation'has start-ed.

The shape of the blank 16 produced by my invention is to be contrasted with that of blank 21 of the character heretofore produced.

' The latter has the intermediate iiange 22 and a mold to form a blank,

theconstricted end portion 23 which results in a moil having a constricted opening lnsufi ficient to allow the passage of the lament mount during the manufacture of the .lamp or similar device and requiring a separate operation for its removal. On the other hand the blank 16 as nrodvced by my invention has no constricted end portion and the clamping thereof in the blowing spindleproduces an end flange by means of which alone the blank is held, thus allowing the formation of a neck opening in thebulb large enough to take the mount without requiring the removal of a moil.

What I claim as new and desire to secure by LettersPatent of the United States, 1s

1. The method of making a bulbffor an incandescent lamp or similar article which consists in drawing molten lass by-suction into upon a blowing spindle and supportin it by clamping the lower edge thereof to t etop of said spindle.

2. The method of making a bulb for an inl candescent lamp or similar article which coni sists in drawing molten glass bysuction into a mold free of laterally re-entrant portions `to form a blank, dropping vsaid blank upon a 4blowing spindle vand supportin it by clamping the lower edge spindle.

thereofkto t e top of said rapping said blank v i .y The method of making a bulb for ini' candescent electric lamps and similar articles which consist-sin gathering by suction from a supply of molten glass a blank having its ttorn diameter at least as great as that of any other diameter thereof, clamping the lower edge of said blank to a blowing spindle and then blowing said article.

4. The method of making a bulb forlincandescent electriclamps and similar articles which consists in gathering by suction from a supply of molten'glass a blank having its bottom diameter at least as great as that of any other diameter thereof, clamping the lower edge of said blank to a blowing-spindle and hereunto set'my"l isol 

